Green roofs are growing in popularity within architecture and the building industry. They are great for the environment in a number of ways and installing one on your home can make financial sense as well!
These living roofs increase biodiversity, providing vegetation in areas that could benefit from plant species. These plants in turn attract insects and birds. Large green roofs can also act as carbon sinks that absorb CO2 and produce oxygen. The UK’s biggest green roof is in Birmingham.
Another great advantage of the soil in a green roof is that it can absorb rainwater, which slows the run-off from a downpour. This helps reduce the chance of localised flooding in built-up areas. Many more demonstrable benefits can be found here.
However, for a vegetated roof to be environmentally beneficial then the installation has to take into account the materials used. A green roof needs many layers and a strong structure below to support it, all of which could add up to a large amount of embodied energy.
But there are also great financial benefits to a green roof. If properly installed, a green roof can increase the energy efficiency of a building. The thermal mass of a soil roof makes it really effective at insulating the building below. So heating usage decreases by retrofitting a roof to be a green one. Flat un-vegetated roofs can be 20ºc hotter than living roofs!
Cities make ideal surroundings for green roofs. Vegetated roofs can provide fantastic gardens in urban areas where space is limited. There is strong evidence that these natural surroundings improve health and well-being.
Did you know, all new roofs in Copenhagen that are less than 30° steep must be a green roof? This planning obligation was introduced in 2010 as part of Copenhagen’s push to be carbon neutral. Whilst Copenhagen is a much smaller city than London or Manchester, this sustainable initiative could be perfect for improving Britain’s urban districts.
But what if your sustainable design or retrofit can not support a green roof?
Well, green concrete could soon be a feasible construction material for sustainable architects. Biological concrete has been developed by the Structural Technology Group, which could create ‘living’ buildings. The concrete supports the growth of organisms that can help to reduce CO2 levels in the atmosphere.
All of this goes to show that, while turf roofs have been around for hundreds of years, there is life in the old dog yet!